A numerical control (hereinafter, NC) device generally includes an NC control unit, an instruction unit primarily constituted by an NC operation panel, and a drive unit constituted by a servo amplifier, a main shaft amplifier, a motor, or a detector. Computerized NC (CNC) devices that have high-performance dedicated microcomputers incorporated therein and that can perform complicated and advanced control with high reliability are also currently used as NC devices.
The NC device can also execute sequence control according to an input signal from a sensor, a switch, or the like installed in a machine tool. Operations that are controlled are operations associated with the machine tool such as tool replacement and swarf removal. A program describing a series of machining operations for the NC device to perform is referred to as “NC programming”. This program has the tool routing, the machining conditions, or the like required for machining and is represented in the form of command for the NC device to follow. The NC program can be downloaded from an external program automatic-generation device to the NC device or it can be directly input through the NC operation panel.
Generally, the NC device is used in fields requiring higher-speed and higher-accuracy control, and such qualities cannot be implemented by a system established by combining a general-purpose sequencer and a general-purpose servo. This type of NC device can execute control having high real-time performance that provides a fast response equal to or lower than 0.5 milliseconds in a servo system and being highly accurate so as to provide control at the 0.1-μm level. The NC device also has stable characteristics that enable high-level servo acceleration/deceleration control that does not cause vibration while executing control having a high real-time performance and that is highly accurate. The NC device can also execute correction control on the machine due to backlash, torsion, flexure, stretch, and shrinkage occurring in accordance with the stiffness factor of the machine. Furthermore, the NC device can also execute synchronous control such that one workpiece is machined simultaneously using a plurality of gears, such as moving to another machining area without stopping the rotation of a workpiece that is being rotated.
In recent years, to rapidly address any change in the status of production or the like in a factory, it is important to promptly refer to or evaluate changes in information related to production taking place in various production facilities. Therefore, the machine tool is also required to accurately and promptly refer to or evaluate machining information in order to rapidly respond to a change in the machining status. For this purpose, an NC device having a machining-information communication function has been proposed (see, for example, Patent Literature 1).
Patent Literature 1 discloses a system with a structure in which an FA (Factory Automation) network having programmable controllers, a data file having data obtained from the programmable controllers stored therein, and a user application are connected via a data management device. The data management device functions as middleware between the programmable controllers and the data file or the user application in order to perform a process of storing data collected from the PLCs in the data file or notifying the user application thereof.